Method and apparatus for filling a steam chamber

ABSTRACT

A method and apparatus for filling a steam chamber. In one exemplary embodiment, a steam chamber is placed in selective communication with a vacuum pump and a heat transfer medium, such as a source of deaerated water. The steam chamber is then placed in communication with the vacuum pump, which draws a vacuum on the steam chamber and begins removing air from the interior thereof. Once a sufficient vacuum has been drawn on the steam chamber and substantially all of the air removed therefrom, the steam chamber may be placed in communication with the heat transfer medium. In one exemplary embodiment, the heat transfer medium is deaerated water. A predetermined amount of heat transfer medium is then allowed to fill the steam chamber. Once the predetermined amount of deaerated water has been received within the steam chamber, a steam chamber may be sealed.

This application is a divisional application of U.S. patent applicationSer. No. 11/856,186, filed Sep. 17, 2007, the full disclosures which areincorporated herein by reference in their entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a method and apparatus for filling asteam chamber.

2. Description of the Related Art

Steam chambers, such as those used in manufacturing steam griddles, arefilled with water and/or other boilable fluids and sealed. By activatinga heating element, the fluid within the steam chamber is converted froma liquid to a gas, which rises within the steam chamber. When the gascontacts the top surface of the steam chamber, heat is transferredthereto. The opposing side of the top surface, i.e., the surface on theexterior of the steam chamber, may act as a cooking surface upon whichfood is placed to be cooked. During operation of the steam chamber, anyair that is sealed within the chamber may prevent the rising gas fromdirectly contacting the top surface, resulting in a cold spot on thecooking surface. These cold spots create areas of lower temperature onthe cooking surface of the steam chamber, which may increase the cookingtime of food positioned thereon.

SUMMARY

The present invention relates to a method and apparatus for filling asteam chamber. In one exemplary embodiment, a steam chamber is placed inselective communication with a vacuum pump and a heat transfer medium,such as a source of deaerated water. The steam chamber is then placed incommunication with the vacuum pump, which draws a vacuum on the steamchamber and begins removing air from the interior thereof. Once asufficient vacuum has been drawn on the steam chamber and substantiallyall of the air removed therefrom, the steam chamber may be placed incommunication with the heat transfer medium. In one exemplaryembodiment, the heat transfer medium is deaerated water. A predeterminedamount of heat transfer medium is then allowed to fill the steamchamber. Once the predetermined amount of deaerated water has beenreceived within the steam chamber, the steam chamber may be sealed.

Advantageously, by using the combination of a vacuum to remove air fromthe steam chamber and filling the chamber with deaerated water, thelikelihood of having any substantial amount of air within the steamchamber after sealing the same is lessened. For example, even whensubstantially all of the air within a steam chamber is removed, when thewater within the steam chamber is heated, dissolved oxygen and otherconstituents of air may be released in gaseous form. This release of thedissolved constituents of air in the gas phase creates pockets withinthe steam chamber adjacent the cooking surface. As a result, cold spotsmay be formed on the cooking surface. By substantially eliminating boththe air from the steam chamber and the dissolved constituents of airfrom the water, the formation of cold spots on the cooking surface issubstantially eliminated. This provides the ability to create andmaintain a uniform temperature across the entirety of the cookingsurface. This uniform temperature is advantageous in that it providesstandardized cooking times and facilitates more accurate temperatureadjustment and control.

In one form thereof, the present invention provides an apparatus forfilling a steam chamber having a cooking surface and a fill port, theapparatus including a source of deaerated water; a vacuum pump; and avalve configured for connection to the steam chamber, said valve inselective communication with said source of deaerated water and saidvacuum pump.

In yet another form thereof, the present invention provides a method offilling a steam chamber, including the steps of drawing a vacuum on thesteam chamber to substantially evacuate the steam chamber; filling thesubstantially evacuated steam chamber with a predetermined amount offluid transfer medium; and sealing the steam chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective view of a steam griddle including a steamchamber;

FIG. 2 is a schematic view of the apparatus used to fill the steamchamber of FIG. 1;

FIG. 3 is a fragmentary perspective view of a portion of the apparatusshown schematically within dashed line 3-3 of FIG. 2;

FIG. 4 is a fragmentary assembly view of the steam chamber of FIG. 1 anda cap;

FIG. 5 is a fragmentary assembled view of the steam chamber and cap ofFIG. 4;

FIG. 6 is a fragmentary perspective view of a portion of the apparatusshown schematically within dashed line 6-6 of FIG. 2;

FIG. 7 is a fragmentary perspective view of a portion of the apparatusshown schematically within dashed line 7-7 of FIG. 2.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplification set out hereinillustrates a preferred embodiment of the invention, in one form, andsuch exemplification is not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

Referring to FIG. 1, steam griddle 10 is depicted including steamchamber 12 having top and bottom walls including a first, top surface,such as cooking surface 14, and a second, bottom surface 16,respectively. While described and depicted herein with specificreference to steam chamber 12 of steam griddle 10, the present inventionmay be utilized in conjunction with any steam heated food service orfood preparation device, such as a steam jacketed kettle, e.g., thesteam jacketed kettle 200 (FIG. 2). Cooking surface 14 and bottomsurface 16 are connected by a plurality of walls 18. Steam chamber 12 issupported by frame 20 having a plurality of legs 22 extending therefrom.Contained within steam chamber 12 or positioned adjacent bottom surface16 of steam chamber 12 is a heating element (not shown), such as anelectric coil or gas burner. Actuation of knobs 24, 26 activate theheating element to boil a heat transfer medium, such as deaerated water,contained within steam chamber 12. As the heat transfer mediumevaporates, the resulting gas rises in the direction of cooking surface14 and imparts heat to cooking surface 14 for cooking food placedthereon.

Referring to FIG. 2, a schematic is shown representing an apparatus forevacuating and filling steam chamber 12, with deaerated water as theheat transfer medium. Referring to FIGS. 2 and 3, T-valve 28 isconfigured for threaded engagement with fill port 30, shown in FIG. 4,of steam chamber 12. In another exemplary embodiment, T-valve 28 isconfigured for flange engagement with fill port 30. Specifically,T-valve 28 includes an internally threaded bore designed to threadablyengage the exterior surface of fill port 30. While a T-valve isdescribed and depicted herein for connection with fill port 30, anyknown valve design capable of starting and stopping the flow of a fluidtherethrough, such as a ball valve, may be used. Once T-valve 28 isconnected to fill port 30, rod 32 is moved upward in the direction ofarrow A (FIG. 3) to place steam chamber 12 in fluid communication withpipes 34, 36. Connected to T-valve 28 by pipe 34 is pressure gauge 35.This allows for the operator to readily determine the pressure withinT-valve 28 and, correspondingly, vacuum chamber 12.

Connected to the opposite side of T-valve 28 by pipe 36 is ball valve38, which is actuated to control the transfer of fluid from pipe 40 tosteam chamber 12. Connecting pipe 40 to pipe 42 is flange connection 44.Flange connection 44 is of the type commonly used with high vacuumservice applications to prevent outside air contaminants frominfiltrating the system when the same is placed under vacuum. Connectedto pipe 42 are ball valve 48, which is connected to a vacuum source, andball valve 46, which is connected to a source of deaerated water asdescribed below. Specifically, referring to FIG. 2, connected to ballvalve 48 is pipe 50, ball valve 54, and pipe 52. Vacuum pump 56 isconnected to pipe 52 and, when ball valves 54, 48, 38 are open, draws avacuum on steam chamber 12, as described in detail below. In oneexemplary embodiment, vacuum pump 56 is a two-stage vacuum pump. In thisembodiment, vacuum pump 56 used both stages to draw a vacuum on steamchamber 12 and uses a single stage to draw a vacuum on deaerator 74, asdescribed in detail below. Additionally, a vacuum gauge may be added topipe 50 to determine that vacuum pump 56 has achieved a sufficient levelof vacuum in pipe 50 and, correspondingly, steam chamber 12.

In another exemplary embodiment, high vacuum pump 57, shown in FIG. 2 indashed lines, is connected directly to pipe 40 by flange connection 44to draw a vacuum on steam chamber 12. In this embodiment, pipe 42 isdisconnected from flange connection 44 and pipe 59 is connected toflange connection 44. Ball valve 38 is then opened, placing high vacuumpump 57 in fluid communication with stem chamber 12 via pipe 36 andT-valve 28. Once a sufficient vacuum is achieved, e.g., the vacuumwithin steam chamber 12 is approximately 500 mTorr or less, ball valve38 is closed and pipe 59 is disconnected from flange connection 44. Pipe42 may then be connected to flange connection 44 and ball valve 48, 54opened to draw a vacuum on pipe 42 and evacuate the same via vacuum pump56. Ball valve 48 may then be closed and a supply of deaerated waterdelivered to steam chamber 12, as described below.

To create deaerated water to fill the interior of steam chamber 12, asdescribed in detail below, a supply of distilled water is held withintank 58. Water flows in serial order from tank 58 through pipe 60, ballvalve 62, pipe 64, ball valve 66, pipe 68, ball valve 70, and pipe 72 toarrive at deaerator 74. Thus, during filling of steam chamber 12, ballvalve 80 remains closed to force water through open ball valve 66 andalong the path previously described. However, to prime the deaerationsystem or to otherwise purge air from the same, ball valve 66 may beclosed to diverted distilled water from tank 58 through pipe 75.Distilled water from tank 58 may then be pumped by water pump 77 throughthe deaeration system to prime the deaeration system in preparation forfilling steam chamber 12. Additionally, in the event air has infiltratedthe deaeration system, e.g., if vacuum pump 56 is turned off for anextended period of time, water pump 77 may be used to flush thedeaeration system by forcing distilled water from tank 58 through thedeaeration system.

Deaerator 74 includes a plurality cylindrically shaped semi-permeablemembranes extending from end 76 of deaerator 74 to opposing end 78. Asdistilled water from tank 58 enters deaerator 74, the distilled water isforced into a space between the outer wall of the deaerator membrane andthe inner wall of deaerator housing 79. At the same time, a vacuum isdrawn on the hollow interior of the deaerator membrane. By creating anarea of lower pressure in the hollow interior of the membrane, dissolvedgasses within the distilled water are pulled through the deaeratormembrane and into the hollow interior, while the flow of distilled waterinto the hollow interior of the membrane is prevented. Specifically, thedeaerator membrane has small hydrophobic pores that prevent the passageof liquid water, but allow for the passage of gaseous substances, suchas dissolved air, therethrough. Advantageously, by utilizing deaerator74, the need to heat the distilled water contained within tank 58 todeaerate the same is eliminated. Thus, the temperature of the distilledwater traveling through the deaeration system is maintained at atemperature substantially similar to the temperature of the ambientenvironment. For example, the temperature of the distilled water may bemaintained below 100°, 125°, 150°, or 212° Fahrenheit during each stepof the present process.

To create a vacuum in the hollow interior of the deaerator membrane,vacuum pump 56 is placed in fluid communication with the center of thedeaerator membrane. Specifically, ball valve 48 is closed and ball valve82, adjacent vacuum pump 56, is opened to place vacuum pump 56 in fluidcommunication with vacuum regulator 84. Vacuum regulator 84 helps tokeep the pressure within deaerator 74, i.e., the vacuum created byvacuum pump 56, constant. Positioned adjacent vacuum regulator 84 andits corresponding piping is pressure gauge 86. Pressure gauge 86provides constant, visual feedback to the operator regarding thepressure within pipe 88.

As shown in FIG. 2, pipe 88 is connected to end 78 of deaerator 74 andis in fluid communication with the hollow interior of the deaeratormembrane. Similarly, pipe 90 is connected to end 76 of deaerator 74 andis in fluid communication with the interior of the deaerator membraneand pipe 88. Thus, a vacuum is drawn at both end 76 and end 78 ofdeaerator 74. Connected to pipe 88 is ball valve 92 and filter 94.Filter 94 provides vent 96 for releasing vacuum from deaerator 74.Additionally, connected to pipe 90 is ball valve 98 and drain pipe 100.By opening ball valve 98, condensed water that may have inadvertantlypassed through the deaeration membrane may be drained from the system.

The now deaerated water exiting deaerator 74 travels through pipe 102 toa flow controller, such as flow indicating controller 104. Flowindicating controller 104 monitors the flow of deaerated watertherethrough and, once the amount of water passing through pipe 102 andinto pipe 106 reaches a programmed, predetermined amount, flowindicating controller 104 activates solenoid valve 108 to stop the flowof water through pipe 106. Additionally, positioned between pipe 106 andsolenoid valve 108 is needle valve 110. Needle valve 110 may be adjustedso that the speed with which water passes through solenoid valve 108and, ultimately, enters steam chamber 12 may be varied. After exitingsolenoid valve 108, deaerated water travels through pipes 112, 42, 40,36 and ball valves 46, 38 to enter T-valve 28.

To fill a steam chamber utilizing the above-described apparatus, thefollowing method may be utilized. Referring to FIG. 3, with T-valve 28attached to fill port 30 of steam chamber 12, as described in detailabove. Once in this position, ball valves 38, 46 are closed and ballvalves 54, 48, 82 opened. Vacuum pump 56 may then be activated, causingvacuum pump 56 to draw a vacuum on pipes 52, 50, 42, 40. Once asufficient vacuum has been drawn, as indicated by pressure gauge 86,ball valve 38 is opened and rod 32 is actuated in the direction of arrowA to place T-valve 28 in fluid communication with the interior of steamchamber 12. As a result, a vacuum is drawn via pipe 36 and T-valve 28 onsteam chamber 12. Once pressure gauge 35 indicates a pressure equal toor below a predetermined, acceptable pressure, ball valve 48 is closed.

At this point, deaerated water must be added to steam chamber 12. Tofacilitate adding the appropriate amount of deaerated water, flowindicating controller 104 is programmed to stop the flow of deaeratedwater after a predetermined amount has passed therethrough. Thispredetermined amount corresponds to the amount of deaerated water neededto fill steam chamber 12 to the desired level. Once flow indicatingcontroller 104 is programmed, ball valve 82 is opened, allowing vacuumpump 56 to draw a vacuum on the interior of the deaerator membrane viapipes 88, 90. With ball valves 92, 98 closed, the vacuum on the interiorof the deaerator membrane increases. Ball valves 62, 66, 70, 46, 38 arenow opened to allow distilled water to flow from tank 58 through pipes60, 64, 68, 72 and deaerator 74, in serial order.

The now deaerated water continues in serial order through pipe 102, flowindicating controller 104, pipe 106, needle valve 110, solenoid valve108, pipe 112, ball valve 46, pipe 42, flange connection 44, ball valve38, pipe 36, and T-valve 28 to enter steam chamber 12. Due to the vacuumpreviously drawn on steam chamber 12, the deaerated water will be suckedfrom tank 58, which is maintained at atmospheric pressure, into steamchamber 12 along the path described above. As a result, needle valve 110may be adjusted to regulate the speed at which deaerated water passestherethrough and ultimately enters steam chamber 12. As the deaeratedwater flows, flow indicating controller 104 registers the amount ofdeaerated water that has passed therethrough and may display the amountremaining to fill steam chamber 12 to the predetermined level.Alternatively, flow indicating controller 104 may display the totalvolume of deaerated water that has passed therethrough. Once flowindicating controller 104 determines that the programmed amount ofdeaerated water has passed therethrough, solenoid valve 108 is actuatedinto the closed position via electronic connection 120.

Once solenoid valve 108 has been closed, ball valve 38 is closed and rod32 depressed in the direction of arrow B of FIG. 3. Referring to FIG. 2,attached to the end of rod 32 on post 122 is plug 124, which isdimensioned to substantially prevent fluid communication with steamchamber 12. Plug 124 is externally threaded and configured tothreadingly engage the interior of fill port 30. By depressing rod 32 inthe direction of arrow B, plug 124 engages the interior of fill port 30and, as rod 32 is rotated, plug 124 threading engages fill port 30 tofirmly seat plug 124 therein. Once plug 124 is seated within fill port30, rod 32 may be actuated in the direction of arrow A and post 122disengaged from plug 124. T-valve 28 may then be unthreaded from theexterior of fill port 30. In this manner, fill port 30 is plugged andthe vacuum within steam chamber 12 maintained. With T-valve 28 removedfrom fill port 30, cap 126, shown in FIGS. 4-5, is positioned over fillport 30 and secured thereto via weld 128.

Although the specific embodiment of the apparatus described herein setsforth various connections for drawing a vacuum on a steam chamber andfilling the same with deaerated water, any myriad of connections,valves, piping, or other mechanisms may be utilized to accomplish thesame result. Thus, while this invention has been described as having apreferred design, the present invention can be further modified withinthe spirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

1. An apparatus for filling a steam chamber having a cooking surface anda fill port, the apparatus comprising: a source of heat transfer medium;a vacuum pump; and a valve configured for connection to the steamchamber, said valve in selective communication with said source of heattransfer medium and said vacuum pump.
 2. The apparatus of claim 1,wherein said heat transfer medium comprises deaerated water.
 3. Theapparatus of claim 2, wherein said source of heat transfer mediumfurther comprises a deaerator and a vacuum pump.
 4. The apparatus ofclaim 3, wherein said deaerator comprises a membrane separator.
 5. Theapparatus of claim 1, further comprising a flow controller incommunication with said source of heat transfer medium, whereby saidflow controller starts and stops the flow of heat transfer medium tosaid valve when said valve is in communication with said source of heattransfer medium.
 6. The apparatus of claim 1, wherein said valve isconfigured for connection to the fill port of the steam chamber, saidvalve further comprising a rod having a plug carried thereon.
 7. Theapparatus of claim 6, wherein said plug is dimensioned to substantiallyprevent fluid communication with the steam chamber.
 8. The apparatus ofclaim 7, wherein said rod is moveable between a first position in whichsaid valve is in fluid communication with the steam chamber and a secondposition in which said plug substantially prevents fluid communicationbetween said valve and said steam chamber.
 9. The apparatus of claim 7,wherein said plug includes threads formed thereon, said threadsconfigured to threadingly engage corresponding threads on the fill portof the steam chamber. 10-21. (canceled)
 22. The apparatus of claim 1,wherein the heat transfer medium is liquid water.
 23. The apparatus ofclaim 22, wherein the membrane separator includes a semi-permeablemembrane.
 24. The apparatus of claim 23, wherein the semi-permeablemembrane includes small hydrophobic pores that prevent the passage ofliquid water by allow for the passage of gaseous substancestherethrough.
 25. The apparatus of claim 23, wherein the vacuum pump isconfigured to draw a vacuum on an interior of the membrane separator topull dissolved gases through the semi-permeable membrane while thesemi-permeable membrane prevents passage of the heat transfer mediumtherethrough.
 26. A valve configured to be attached to a chamber and awater tank, the valve comprising: a rod movable having a plug carriedthereon, the plug dimensioned to substantially prevent fluidcommunication with the chamber, wherein said rod is moveable between afirst position in which said valve is in fluid communication with thechamber and a second position in which said plug substantially preventsfluid communication between said valve and said chamber.
 27. The valveof claim 26, wherein said plug includes threads formed thereon, saidthreads configured to threadingly engage corresponding threads on a portof the chamber.
 28. The valve of claim 27, wherein said threads on saidplug are configured to threadingly engage said corresponding threads onsaid port of the chamber when the rod is rotated.
 29. The valve of claim26, wherein the valve is a T-valve.
 30. The valve of claim 26 furthercomprising a pressure gauge, wherein the pressure gauge is in fluidcommunication with the chamber when the rod is in the first position andthe pressure gauge is not in fluid communication with the chamber whenthe rod is in the second position.
 31. The valve of claim 26 incombination with a steam chamber, a source of heat transfer medium, anda vacuum pump, wherein the valve is connected to the steam chamber andin selective communication with the source of heat transfer medium andthe vacuum pump.